The principle of spectral confocal sensor and color laser coaxial displacement meter is the same, it is the same thing, just because different manufacturers promote their products and redefine the name of their products. They are based on the principle of confocal spectroscopy, the visible light is dispersed through the lens group into the spectrum of red, orange, yellow, green, blue, indigo, violet seven colors, and then the reflection principle is used to convert the corresponding displacement value according to the reflected wavelength.

As we all know, natural light is a kind of white light, and white light is not the purest light, but composed of many monochromatic light. There may be Angle deviation when light propagates in different media, but the actual white light irradiation in different media will produce a lot of single line light refraction.

Optical materials (lenses) have different refractive indices of monochromatic light with different refractive indices, that is, wavelengths with larger refractive indices have different refractive indices of shorter wavelengths, and wavelengths with longer refractive indices have smaller refractive indices (this is also the reason why the telescope is called different color difference). The same thin lens corresponds to different monochromatic light, and each monochromatic light has different focal lengths, depending on the wavelength of light from short to long. Their image points are arranged on the lens from near to far along the optical axis (different monochromatic light has different wavelengths), resulting in what is called chromatic aberration lens.

Errors in the color lens cause the image to produce streaks or halos. In photographic equipment, special treatment should be taken to minimize imaging problems caused by aberration lens errors. Common elimination methods include double gluing system and double separation system.